A two-stroke free piston internal combustion engine used as drive means is known. Such an engine includes two coaxial cylinders which are positioned one behind the other, with each cylinder containing a pair of pistons that operate in opposition to one another. The individual pistons of each piston pair, that move in the same direction, are interconnected with one another. Each piston pair delimits a combustion chamber in its respective cylinder, so that with alternate firing of the cylinders, the pistons of each piston pair move back and forth in opposite directions. In this process, the movement energy is tapped at the interconnection of the pistons, and can be used, for example, for driving an electric generator.
It is an object of the present invention to provide a method for controlling the operation of this type of a device when used for generating electric energy, in a way that effects stable operation of the free piston internal combustion engine.